1. Field of the Invention
This invention relates to an image forming system for forming an image on a recording medium, and more particularly to an image forming system provided with a power-saving mode where the power supply to a part thereof is interrupted when the operator does not operate the system for a predetermined time interval.
2. Description of the Related Art
There have been proposed various image forming systems provided with a power-saving mode, where the power supply to a part thereof is interrupted when the operator does not operate the system for predetermined time interval, for instance, in a stencil printer in which a stencil is made on the basis of image data and print is made on the basis of the stencil or a copy system.
For example, there has been proposed, as disclosed in Japanese Unexamined Patent Publication No. 2001-138473, an image forming system with a power-saving mode where, when the operator does not operate the system for predetermined time interval, the electric power is supplied only to a unit for receiving image data from an external unit and the electric power supply to the other part including the parts for driving the stencil making system and the printing system is cut. Further in U.S. Pat. No. 6,763,473, there has been proposed a system where the electric power supply to the scanner and/or the image processing system is cut when the image forming system is not operated for a long time.
In the systems disclosed in Japanese Unexamined Patent Publication No. 2001-138473 and U.S. Pat. No. 6,763,473, the power supply to all the parts of the system is resumed in response to any operation of the operator on the system.
However, it takes a time for the operator to actually start, for instance, printing. For example, it takes a certain time for the operator to set predetermined items, for instance, through the control panel of the printer or to actually instruct to print after he or she sets the printing papers. It is wasteful to supply the electric power to all the parts of the system in such times though the stencil making action or the printing action has not been started yet.
Further, though the power supply to the control panel or the like is generally cut in the power-saving mode, it takes a long time for the control panel to accept input of an instruction to operate the system when the power supply to the control panel or the like is cut. Further, the contents of the preceding instruction are sometimes reset when the operator's input is slow and the system is turned to the power-saving mode. In this case, it is necessary for the operator to input again the instruction to operate the system, which is troublesome for the operator. In order to release himself or herself, the operator can cancel the power-saving mode, which gives rise to a problem that power reduction cannot be obtained after all.